Crystallized organopolysiloxane-polycarbonate block polymers and method for making them

ABSTRACT

Random alternating organopolysiloxane-polycarbonate block polymers can be crystallized by contacting the block polymer with a methylalkylketone in the vapor or liquid state. The resulting crystallized organopolysiloxane-polycarbonate block polymers exhibit improved physical characteristics, such as tensile strength (psi) and improved resistance to distortion at elevated temperature. The crystallized organopolysiloxane-polycarbonate block polymers can be employed as dielectrics and as permselective membranes for separating gases and vapors.

United States Patent Le Grand [451 July 25, 1972 [72] Inventor: DonaldC. Le Grand, Burnt Hills, NY

[73] Assignees General Electric Company [22] Filed: March 2, 1970 21Appl. No.: 15,472

[52] U.S. Cl. ..260/824 R, 55/522, 252/632, 252/63.7, 260/47 XA [5 1]Int. Cl ..C08g 47/10 [58] Field of Search ..260/824, 47 XA, 32.8 SB

[56] References Cited UNITED STATES PATENTS 3,189,662 6/1965 Vaughn..260/824 3,306,873 2/1967 Von Falkai et al.. .260/47 XA 3,379,7904/1968 Krauss et al. ..260/824 OTHER PUBLICATIONS Christopher et al.,Polycarbonates, Reinhold Publ. Corp., N.Y. I962 Primary Examiner-SamuelH. Blech Attorney-Richard R. Brainard, Joseph T. Cohen, Paul A. Frank,Charles T. Watts, William A. Teoli, Frank L. Neuhauser, Oscar B. Waddelland Joseph B. Forman 57 ABSTRACT Random alternatingorganopolysiloxane-polycarbonate block polymers can be crystallized bycontacting the block polymer with a methylalkylketone in the vapor orliquid state. The resulting crystallizedorganopolysiloxane-polycarbonate block polymers exhibit improvedphysical characteristics, such as tensile strength (psi) and improvedresistance to distortion at elevated temperature. The crystallizedorganopolysiloxanepolycarbonate block polymers can be employed asdielectrics and as permselective membranes for separating gases andvapors.

6 Claims, 2 Drawing Figures PKTENTEflJuLsmz /n venfor Dona/a 6 Le GrandHis Attorney.

CRYSTALLIZED ORGANOPOLYSILOXANE- POLYCARBONATE BLOCK POLYMERS AND METHODFOR MAKING THEM The present invention relates to a method for inducingcrystallization in organopolysiloxane-polycarbonate block polymers andto the products produced thereby.

Organopolysiloxane-polycarbonate block polymers and methods for makingthem are shown by Vaughn U.S. Pats. Nos. 3,189,662 and 3,419,634,assigned to the same assignee as the present invention. As taught inthese patents, the organopolysiloxane-polycarbonate block polymers haveunique properties which are not possessed by either organopolysiloxanesor polycarbonates. Among'the uses of these materials are surfacecoverings for appliances, insulation, coatings for rods and wires,binding material for parts and laminates, adhesive formulations, etc.These materials also can be employed to make room temperaturevulcanizing organopolysiloxanepolycarbonate compositions as taught byVaughn US. Pat. No. 3,419,635 also assigned to the same assignee as thepresent invention. Recently, the organopolysiloxane-polycarbonate blockpolymer films have been found to be valuable permselective membranes forliquid and gas separation such as providing for oxygen separation froman oxygen containing gas mixture. In addition to exhibiting a highoxygen permeability, the copolymers are thermoplastic and can beadvantageously heat sealed into sheets or containers to a desired sizeor shape. In medical applications, due to the thermoplastic propertiesof the copolymers, undesirable distortion of the preform can result attemperatures around 100' C required for sterilization. As a result, theemployment of the block polymers as a medical too] often has beenrestricted to applications which did not require sterilization.

The present invention is based on the discovery that shapedorganopolysiloxane-polycarbonate block polymers having improved heatdistortion and tensile (psi) can be obtained by contacting the preformedblock polymer with certain methylalkylketones in the vaporous or liquidstate. It has been found that as a result of such treatment,crystallization is induced into the block polymer which is dramaticallyillustrated by comparing FIG. 1, showing the X-ray diffraction patternof the untreated block polymer, and FIG. 2, the treated block polymer.

There is provided by the present invention, a process for inducingcrystallization into an organopolysiloxane-polycarbonate block polymerwhich comprises contacting the block polymer with a methylalkylketone ata temperature in the range of between to 250 C.

Some of the organopolysiloxane-polycarbonate block polymers which can beutilized in the invention are illustrated by the following formula,

(Z)u a where n is at least 1, and preferably n is an integer equal tofrom 1 to about 1,000, inclusive, a is equal to from 1 to about 200,inclusive, and preferably b has an average value from about 15 to about90, inclusive, while the ratio of a to b can vary from 0.05 to about 3,inclusive, and when b has an average value of from about 15 to about 90,inclusive, the ratio of a to b is preferably from about 0.067 to about0.45, inclusive, u is an integer equal to from 1 to 4, inclusive, Y is Ais a member selected from the class of hydrogen and 7 R is a memberselected from the class of hydrogen, 5

monovalent hydrocarbon radicals and halogenated monovalent hydrocarbonradicals, R is a member selected from the class of monovalenthydrocarbon radicals, halogenated monovalent hydrocarbon radicals, andcyanoalkyl radicals, and Z is a member selected from the class ofhydrogen, lower alkyl radicals and halogen radicals.

As taught by Vaughn, US. Pat. No. 3,189,662,organopolysiloxane-polycarbonate block polymers can be made by initiallyforming aryloxy chainstopped polydiorganosiloxane by effecting contactbetween a halogen chainstop polydiorganosiloxane having up to about 200chemically combined polydiorganosiloxy units and terminal halogenradicals and dihydric phenol, such as bisphenol in the presence of anacid acceptor, for example pyridine. The resulting mixture containingexcess dihydric phenol is then phosgenated to produce apolydiorganosiloxane-polycarbonate block polymer. Depending upon theblock size of the halogen chainstopped polydiorganosiloxane and therelative weight percent of siloxane and dihydric phenol utilized in thephosgenation mixture, a wide variety of block polymers can be made. Theorganopolysiloxane-polycarbonate block polymers of the present inventioncan contain from 1 to percent by weight of organopolysiloxane blocks,and from 5 to 99 percent by weight of polycarbonate blocks. Preferably,the polycarbonate blocks should have at least about 15 chemicallycombined polycarbonate units.

In addition to the above described organopolysiloxanepolycarbonatesiloxane-polycarbonate block polymers made by the phosgenation ofpolydiorganosiloxane having terminal bisphenol units joined to thepolydiorganosiloxane by aryloxy linkages,organopolysiloxane-polycarbonate block polymers also can be utilizedhaving silicon-carbon linkages joining the polydiorganosiloxane block tothe polycarbonate block as taught in US. Pat. No. 3,419,634 (Vaughn).These siliconcarbon bonded block polymers have improved hydrolyticstability as compared to the block copolymers having aryloxy siliconlinkages. Phosgenation of a mixture of the dihydric phenol andpolydiorganosiloxane having terminal hydroxyorganodiorganosiloxy units,such as dimethyl hydroxybutylsiloxy units, can provide for suchhydrolytically stable block polymers.

in addition to the aforedescribed method for inducing crystallizationinto organopolysiloxane-polycarbonate block polymers, there also isprovided by the present invention crystallizedorganopolysiloxane-polycarbonate block polymers comprising (A) from I to95 percent by weight of polydiorganodisiloxane composed from about 2 to200 chemically combined diorgansiloxy units consisting essentially ofdialkylsiloxy units which are joined to each other bysilicon-oxygen-silicon linkages, wherein each of the silicon atoms hastwo organo radicals attached by a carbon-silicon bond, and (B) from 99to 5 percent by weight of an intercondensation product of a dihydricphenol and a carbonyl halide where said polydiorganosiloxane and saidintercondensation product is joined by a linkage selected fromaryloxy-silicon and carbonsilicon.

The crystallization in the organopolysiloxane and polycarbonate blockpolymer can be determined by X-ray diffraction or by use of aDifferential Scanning Calorimeter. Experience has shown that thecrystallized organopolysiloxane and polycarbonte block polymers havemelting points between about C to about 275 C as determined by aDifferential Scanning Calorimeter. A technique which can be employed tomeasure the melting temperature of the crystallized block polymer isshown by ES. Watson, MJ. ONeill, 1. Justin and N. Brenner, ADifferential Scanning Calorimeter for Quantitalive Differential ThermalAnalysis, Anal. Chem. 36, p. L233 1964).

The methylalkylketones which can be employed in the practice of theinvention are, for example, methylethylketone, methylpropylketone andmethylisobutylketone and ketones having at least one methyl radical andan alkyl radical containing from two to eight carbon atoms.

The crystallized organopolysiloxane-polycarbonate block polymers of thepresent invention can be employed as permselective membranes and asdielectrics when utilized in the form of films. In addition, prior tocrystallization, the organopolysiloxane-polycarbonate block polymers canbe molded into a preform, such as a gasket, extruded in the form offibers, etc., and then treated by the method of the invention to improvethe physical properties of such preform.

In the practice of the invention, the organopolysiloxanepolycarbonateblock polymer, hereinafter referred to as the block polymer, iscontacted with the methylalkylketone, hereinafter can be referred to asthe dialkylketone, to effect the crystallization of the block polymer.

Contact between the dialkylketone and the block polymer can be effectedwhen utilizing the dialkylketone in the form of a liquid or vapor.Preferably, the block polymer is utilized in the form of a film whichhas been cast, molded or extruded. However, block polymer shaped to anydesired configuration can be benefited by the method of the invention.Contact temperatures which can be employed to induce crystallization inthe block polymer can vary widely depending upon time of contact, weightpercent of polycarbonate in the block polymer, degree of crystallizationdesired in the block polymer, polycarbonate block size, etc. Atemperature in the range of between about 0 to 250 C can be employed,while it is preferred to operate at about room temperature since, underthese conditions, liquid contact with the dialkylketone, such asimmersion, can be effected.

Crystallization can be induced instantaneously upon contact between thedialkylketone and the block polymer. Desirable results can be achievedin 10 minutes, more or less, if the block polymer is immersed in thedialkylketone at room temperature. Extended contact, such as an hour ormore, can induce crystallization beyond desirable limits and render theblock polymer less useful in particular applications. Generally if theblock size of the polycarbonate is at least about 15 chemically combinedpolycarbonate units, which can be determined by method of NMR, at leasta limited degree of crystallization will occur upon immediate contactbetween the block polymer and the dialkylketone under the conditionspreviously described. Crystallization will progress throughout the blockpolymer until a steady state is achieved depending upon contact time.

The degree of crystallization in the block polymer can be determined byuse of X-ray diffraction techniques. Since the application to which thematerial is to be applied may vary widely, the degree of crystallizationrequired also can vary widely. Upon examination of the physicalproperties of the final product after treatment, those skilled in theart can readily determine the time of contact with the dialkylketonerequired under the parameters, such as temperature, and the compositionof the block polymer employed.

in order that those skilled in the art will be better able to practicethe invention, the following examples are given by way of illustrationand not by way of limitation. All parts are by weight.

EXAMPLE 1 Several polydimethylsiloxane-polycarbonate block polymers wereprepared in accordance with the method taught by Vaughn US. Pat. No.3,189,662. Table I shows the density, weight percent ofpolydimethylsiloxane (Si) in the block polymer and the average number ofchemically-combined dimethylsiloxy units in the polydimethylsiloxaneblock (siloxane block size) of block polymers A, B, C and D. The

composition of the respective block polymers were based on the method ofpreparation and nuclear magnetic resonance.

Solutions of each of the above block polymers were made by dissolving 20parts of the respective block polymer in about parts ofmethylenechloride at room temperature. Films were cast from thesolutions onto a glass plate which were then vacuum dried for 24 hours.Test samples were then cut from films A, B, C and D respectively. Thetest samples were a then tested on an lnstron test meter at C todetermine their respective physical properties. it was not possible totest sample D, since the block polymer flowed at about 100 C.

The respective test samples where then immersed in methylethylketone forID minutes at about 25 C. The respective samples were then vacuum dried.Another test sample from film C also was immersed in methylethylketonefor 1 hour at room temperature and vacuum dried. The samples were thentested on the lnstron tester at 150 C following the same procedurepreviously described. The following table shows the average resultsobtained with two samples of each of respective block polymers beforeand after 10-minute immersion in methylethylketone, where UTS isultimate tensile strength (psi) and UE is ultimate elongation on thelnstron Tester at 150 C.

The procedure of Example 1 was repeated except that in place ofmethylethylketone there was employed methylpropylketone andmethylisobutylketone. The test samples were' respectively immersed inthe aforementioned ketones for l0 minutes at about 25 C. The sampleswere then vacuum dried. The samples were found to have thecharacteristic X-ray diffractionpattern as shown in FlG. 2 as comparedto the untreated samples. This showed that crystallization had beeninduced in the samples.

Although the above samples are limited to only some of the very manyvariables within the scope of the present invention, it should beunderstood that the present invention is directed to the treatment of amuch broader variety of organopolysiloxane and polycarbonate blockpolymers and to crystallized block polymers produced thereby.

lclaim:

1. Organopolysiloxane-polycarbonate block polymer having sufficientcrystallized organopolysiloxane-polycarbonate block polymer of theformula,

Z (Z)u LL R u .L Z lt A is a member selected from the class of hydrogenand R is a member selected from the class of hydrogen, monovalenthydrocarbon radicals and halogenated monovalent hydrocarbon radicals, Ris a member selected from the class of monovalent hydrocarbon radicals,halogenated monovalent hydrocarbon radicals, and cyanoalkyl radicals,and Z is a member selected from the class of hydrogen, lower alkylradicals and halogen radicals.

2. Organopolysiloxane-polycarbonate block polymers in accordance withclaim 1, having from 1 to 95 percent by weight of organopolysiloxanecomposed of blocks consisting essentially of chemically-combineddiorganosiloxy units and from 5 to 99 percent by weight of blocks ofpolycarbonate.

3. A block polymer in accordance with claim 2, consisting essentially ofchemically combined blocks of polydimethylsiloxane and the reactionproduct of carbonyl chloride and 2,2-bis(4-hydroxyphenyl)propane.

4. A method which comprises effecting contact at a tem- 6 l I l/ J"peraturc in the range of from 0 to 250 C. of anorganopolysiloxane-polycarbonate block polymer and a methylalkylketoneselected from ketones having at least one methyl radical and an alkylradical containing from two to eight carbon atoms, where saidorganopolysiloxane-polycarbonate block copolymer has the formula,

where n is at least 1, a is equal to from about 15 to about 200,inclusive, b is equal to from about 5 to about 200, inclusive, while theratio of a to b can vary from 0.05 to about 3, inclusive, u is aninteger equal to from I to 4, inclusive, Y is (Z)u R AZ l R (Z)u I A isa member selected from the class of hydrogen and 0 -L 0R R is a memberselected from the class of hydrogen, monovalent hydrocarbon radicals andhalogenated 'monovalent hydrocarbon radicals, R is a member selectedfrom the class of monovalent hydrocarbon radicals, halogenatedmonovalent hydrocarbon radicals, and cyanoalkyl radicals, and Z is amember selected from the class of hydrofien, lower alktyl radicals andhalogen radicals. I

5. e method 0 claim 4, where the methylalkyl ketone ISmethylethylketone.

6. The method of claim 4, where the organopolysiloxanepolycarbonateblock polymer is immersed in methylethylketone.

2. Organopolysiloxane-polycarbonate block polymers in accordance withclaim 1, having from 1 to 95 percent by weight of organopolysiloxanecomposed of blocks consisting essentially of chemically-combineddiorganosiloxy units and from 5 to 99 percent by weight of blocks ofpolycarbonate.
 3. A block polymer in accordance with claim 2, consistingessentially of chemically combined blocks of polydimethylsiloxane andthe reaction product of carbonyl chloride and2,2-bis(4-hydroxyphenyl)propane.
 4. A method which comprises effectingcontact at a temperature in the range of from 0* to 250* C. of anorganopolysiloxane-polycarbonate block polymer and a methylalkylketoneselected from ketones having at least one methyl radical and an alkylradical containing from two to eight carbon atoms, where saidorganopolysiloxane-polycarbonate block copolymer has the formula, wheren is at least 1, a is equal to from about 15 to about 200, inclusive, bis equal to from about 5 to about 200, inclusive, while the ratio of ato b can vary from 0.05 to about 3, inclusive, u is an integer equal tofrom 1 to 4, inclusive, Y is A is a member selected from the class ofhydrogen and R is a member selected from the class of hydrogen,monovalent hydrocarbon radicals and halogenated monovalent hydrocarbonradicals, R'' is a member selected from the class of monovalenthydrocarbon radicals, halogenated monovalent hydrocarbon radicals, andcyanoalkyl radicals, and Z is a member selected from the class ofhydrogen, lower alkyl radicals and halogen radicals.
 5. The method ofclaim 4, where the methylalkyl ketone is methylethylketone.
 6. Themethod of claim 4, where the organopolysiloxane-polycarbonate blockpolymer is immersed in methylethylketone.